A Triple-Responsive and Dual-NIR Emissive Fluorescence Probe for Precise Cancer Imaging and Therapy by Activating Pyroptosis Pathway

Revealing changes in the tumor microenvironment is crucial for understanding cancer and developing sensitive methods for precise cancer imaging and diagnosis. Intracellular hydrogen peroxide (H₂O₂) and microenvironmental factors (e.g., viscosity and polarity) are closely linked to various physiological and pathological processes, making them potential biomarkers for cancer. However, a triple-response theranostic probe for precise tumor imaging and therapy has not yet been achieved due to the lack of effective tools. Herein, we present a mitochondria-targeting near-infrared (NIR) fluorescent probe, VPH-5DF, capable of simultaneously monitoring H₂O₂, viscosity, and polarity through dual NIR channels. The probe specifically detects H₂O₂ via NIR emission (λ_em = 650 nm) and shows high sensitivity to microenvironmental viscosity/polarity in the deep NIR channel (λ_em ≈ 750 nm). Furthermore, the probe not only monitors mitochondrial polarity, viscosity, and fluctuations in endogenous/exogenous H₂O₂ levels but also distinguishes cancer cells from normal cells through multiple parameters. Additionally, VPH-5DF can be employed to monitor alterations in H₂O₂ levels, as well as changes in viscosity and polarity, during drug-induced pyroptosis in living cells. After treatment with VPH-5DF, chemotherapy-induced oxidative damage to the mitochondria in tumor cells activated the pyroptosis pathway, leading to a robust antitumor response, as evidenced in xenograft tumor models. Thus, this triple-response theranostic prodrug offers a new platform for precise in vivo cancer diagnosis and anticancer chemotherapy.